Arterial bypass grafts utilizing autologous artery are being performed in Rhesus monkeys. As the vessels are harvested they will undergo scanning and transmission electron microscopy as well as routine histologic analysis. Vascular samples will be processed for free cell tissue cultures with the goal of maintaining colonies of tissue for metabolic studies. Whole slices of vessels will undergo organ culture studies in the presence of lipid precursors labeled wth C14, H3, and P32. In addition, each sample tissue will have its lipid extracted, separated and quantitated. BIBLIOGRAPHIC REFERENCE: Ratliff, N.B., Fuchs, J.C.A., Pickett, J.P., Hagen, P-O. and Hackel, D.B.: Vein and Arterial Grafts Studied by Interference Contrast Microscopy. Am. J. Path., 78:32 (1975).